Some semiconductor devices utilize semiconductor-on-insulator (SOI) technology, in which a thin layer of a semiconductor (typically having a thickness of a few nanometers), such as silicon, is separated from a semiconductor substrate by a relatively thick electrically insulating layer (typically featuring a thickness of a few tens of nanometers). Integrated circuits using SOI technology offer certain advantages compared to traditional “bulk” technology for Complementary Metal Oxide Semiconductor (CMOS) integrated circuits. For example, SOI integrated circuits typically provide a lower power consumption for a same performance level.
SOI circuits may also feature a reduced stray capacitance, allowing an increase of computation speeds. Furthermore, the latch-up phenomena encountered in bulk technology may be mitigated. Such circuits are commonly used in System on Chip (SoC) and micro electro-mechanical systems (MEMS) applications. SOI circuits may also be less sensitive to ionizing radiations, making them more reliable than bulk-technology circuits in applications where radiation may induce operating problems (e.g., aerospace applications). SOI integrated circuits may include memory components such as Static Random Access Memory (SRAM), as well as logic gates.
One SOI implementation is for enhanced scaling in Ultra-thin Body and BOX (UTBB), or UTBOX, devices. UTBB cells may include an NMOS transistor and a PMOS transistor, both formed in the thin silicon layer which overlies the buried insulating oxide layer. One example UTBOX integrated circuit is disclosed in U.S. Pat. No. 8,482,070 to Flatresse at al., which is hereby incorporated herein in its entirety by reference. The integrated circuit has cells placed in a cell row having a PMOS transmitter including a ground beneath the PMOS transmitter, and an n-doped well beneath the ground and configured to apply a potential thereto. An NMOS transmitter includes a ground beneath the NMOS transmitter, and a p-doped well beneath the ground and configured to apply a potential thereto.
Despite the existence of such configurations, further enhancements in SOI or UTBB devices may be desirable in some applications.